Salt-bridge dynamics control substrate-induced conformational change in the membrane transporter GlpT.

ABSTRACT: Active transport of substrates across cytoplasmic membranes is of great physiological, medical and pharmaceutical importance. The glycerol-3-phosphate (G3P) transporter (GlpT) of the E. coli inner membrane is a secondary active antiporter from the ubiquitous major facilitator superfamily that couples the import of G3P to the efflux of inorganic phosphate (P(i)) down its concentration gradient. Integrating information from a novel combination of structural, molecular dynamics simulations and biochemical studies, we identify the residues involved directly in binding of substrate to the inward-facing conformation of GlpT, thus defining the structural basis for the substrate-specificity of this transporter. The substrate binding mechanism involves protonation of a histidine residue at the bind

SUBMITTER: Law CJ 

PROVIDER: S-EPMC2426824 | biostudies-literature | 2008 May

REPOSITORIES: biostudies-literature